Apparatus and method for retracting brain tissue during brain surgery

ABSTRACT

A method of performing brain surgery on a patient having a skull and brain tissue, that starts by creating an opening, having a rim, in the skull. The method uses an assembly for facilitating brain surgery that includes a curved frame, defining an inward dimension and an outward dimension; a plurality of spatula arm subassemblies, each including a spatula arm frame clamp, releasably attached to the frame, a spatula arm held and supported by the spatula arm frame clamp and a spatula extending from the inward end of the spatula arm of the spatula arm subassembly. The assembly is clamped to the rim and the spatula arms are positioned so that the spatulas engage the brain tissue in a manner that facilitates surgery.

RELATED APPLICATIONS

This application is a continuation of application U.S. Ser. No.16/373,888, filed Apr. 3, 2019, which is incorporated by reference as iffully set forth herein.

BACKGROUND

A brain surgeon performing surgery through an opening created in theskull, is typically faced with the challenge of pushing brain tissue outof the way of a target surgical location and restraining the braintissue during surgery. In many surgical situations, this is done byfinding a natural cleft between the lobes, working a pair of spatulasinto the cleft and then separating the spatulas to separate the braintissue. To keep the tissue separated as the surgeon operates, thespatulas must be held in place. This is typically done by arms that areattached to some article that is held in constant position, relative tothe patient's head. Most typically, the arms are attached to the clampthat is used to stabilize the patients head during surgery, but in somecases the arms are attached to the surgical table. One disadvantage ofthese arrangements is that a long arm is necessary to reach from itsmount. It is difficult to obtain the desired stability with such a longarm, and it may even obstruct the freedom of movement of the brainsurgeon.

SUMMARY

The following embodiments and aspects thereof are described andillustrated in conjunction with systems, tools and methods which aremeant to be exemplary and illustrative, not limiting in scope. Invarious embodiments, one or more of the above-described problems havebeen reduced or eliminated, while other embodiments are directed toother improvements.

In one aspect, the present invention may take the form of a method ofperforming brain surgery on a patient having a skull and brain tissue,that starts by creating an opening, having a rim, in the skull. Themethod uses an assembly for facilitating brain surgery that includes acurved frame, defining an inward dimension and an outward dimension; aplurality of spatula arm subassemblies, each including a spatula armframe clamp, releasably attached to the frame, a spatula arm held andsupported by the spatula arm frame clamp and a spatula extending fromthe inward end of the spatula arm of the spatula arm subassembly. Theassembly is clamped to the rim and the spatula arms are positioned sothat the spatulas engage the brain tissue in a manner that facilitatessurgery.

In addition to the exemplary aspects and embodiments described above,further aspects and embodiments will become apparent by reference to thedrawings and by study of the following detailed descriptions.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are illustrated in referenced drawings. It isintended that the embodiments and figures disclosed herein are to beconsidered illustrative rather than restrictive.

FIG. 1 shows an isometric view of a brain tissue retractor assembly,according to the present invention.

FIG. 2 shows an exploded perspective view of a spatula arm assembly,that forms a part of the brain tissue retractor assembly of FIG. 1 .

FIG. 3 shows an exploded perspective view of a skull clamp arm assembly,that forms a part of the brain tissue retractor assembly of FIG. 1 .

FIG. 4 shows a sectional view of a clamp arm lock, which forms a part ofthe skull clamp arm assembly of FIG. 3 .

FIG. 5 shows a sectional view of a portion of the clamp arm assembly ofFIG. 3 , clamped to the frame of the brain tissue retractor assembly, ofFIG. 1

FIG. 6 is a detail sectional view of a portion of the spatula armassembly of FIG. 2 .

FIG. 7 is a detail partial sectional view of a portion of the braintissue retractor assembly of FIG. 1 , clamped to skull bone andspreading apart brain tissue.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1 , in a first preferred embodiment, a brain tissueretraction assembly 110 takes the form of a hinged circular frame 112,having a set of releasably attached clamp arm-subassemblies 114 andreleasably attached spatula-arm-sub-assemblies 116. Frame 112 defines aninterior or inner direction, meaning further to the interior of theframe, and an exterior or outer dimension, meaning away from theinterior of the frame, or further outside of the frame. Frame 112 isdivided into two semicircular pieces 112 a, hinged together by a pair ofhinges 112 b, which can be each be locked into position by a frame wingbolt 112 c.

Referring to FIGS. 3 and 5 , each clamp arm-sub-assembly 114 includes aclamp arm base 118, having a lock plate 118 a that is opposed to a dog118 b, protruding up from a dog plate 118 c. If a portion of frame 112is interposed between plate 118 a and dog 118 b and a wing bolt 118 d istightened down, then frame 112 is held tightly between dog 118 b andplate 118 a. When wing bolt 118 d is loosened, frame 112 is releasedfrom pressure and base 118 may be moved about frame 112 or removedentirely. A clamp arm 120 is slidingly engaged in a through-hole 118 ein base block 118 f and may be locked in place by locking lever 118 g.In a preferred embodiment, frame 112 is semicircular in cross-section,so that the mutually opposed surfaces of member 118 a and dog 118 b fitconformally about from frame 112.

Each clamp arm terminates at its interior end in a clamp head 122,having a tongue 124 that is brought closer to clamp head by a bolt 126,threaded through a hole in clamp head 122 and then helically engaged ina threaded hold in tongue 124, to tighten tongue 124 and clamp head 122about the rim of a hole created in the skull, thereby holding frame 112in place. Bolt 126 is loosened to loosen tongue 124 and head 122 fromabout the skull, to permit removal of the clamp head 122 and of theoverall retraction assembly 110. Also, tongue 124 can be rotatedrelative to head 122, before being tightened into place by bolt 126. Inone embodiment, the upper surface of tongue 124 and the lower surface ofhead 122 have a coating of a biocompatible and resiliently deformablematerial, such as silicone, to conform to the upper and lower surfacesof the skull hole rim. it is notable, however, that restraining braintissue cannot apply a great force against the skull hole rim, as braintissue is soft and pliable. Accordingly, every element of assembly 110may be made of lightweight material and in thicknesses that do notprovide the strength that might be necessary in other applications, butthat are thin enough so that assembly 110 has a mass of, in oneembodiment, less than 100 grams.

Referring to FIGS. 2 and 6 , each spatula arm subassembly 116 includes aspatula-arm-base 150, including a base block 150 a, and a clamping block150 b that includes an upwardly projecting dog 150 c. A clamping wingbolt 150 d is engaged into a threaded opening, which draws clampingblock 150 b towards base block 150 a, when turned in a first direction,thereby clamping blocks 150 a and 150 b about frame 112. When wing bolt150 d is turned in the opposite direction, base 150 is loosened fromframe 112, for movement along frame 112, or removal from frame 112. Aspatula arm 154 is held in place between two vertically rotatably-ears156, which are in turn held between two wings 158 of a mounting bracket160. A locking wing bolt 162 is tightened to hold spatula arm 154 inplace, so that it cannot be moved inwardly and outwardly, and to holdears 156 in place by pressure from wings 158, so that ears 156 cannot berotated vertically, which would thereby vertically rotate arm 154. Inaddition, bracket 160 is mounted to base 150 so that it can behorizontally rotated, thereby horizontally rotating arm 154. A lockingring 162 is rotatable and helically threaded engagement to a bolt 164,permitting ring 162 to be tightened down against base block 150 a,thereby locking bracket 160, and thereby arm 154, in place againsthorizontal rotation. A spatula 170 extends downwardly at the end of arm154.

In an alternative preferred embodiment spatula arms that are deformableand that hold their shape after deformation are provided. These arms aredeformed into position, holding spatulas to restrain the brain tissue.

Referring to FIGS. 1 and 7 , to use assembly 110, clamparm-sub-assemblies 114 are moved on frame 112 and each clamp arm 120 ismoved relative its base 118, until clamp heads 122 are arranged aboutthe rim 210 of a hole in the patient's skull, and sub-assemblies 114 andarms 120 are locked in place, and clamp heads 122 and tongues 124 aretightened about the rim 210, to hold assembly 110 in place. With spatulaarms 154 in an upwardly tilting orientation, the spatula armsubassemblies 116 are arranged in placement on frame 112, so thatspatulas 170 may be at a correct location and orientation when loweredinto place. Spatula arms 154 are rotated horizontally so that eachspatula 170 is oriented along a cleft in the brain tissue 212. Then(step not shown), while the brain tissue is gently manually retracted,spatula arms 154 are vertically rotated down to place spatulas 170 sothat they will continue to restrain the brain tissue 210 (as shown) whenit is no longer manually restrained. Spatulas 170, in one embodiment,are made of a thin sheet of metal, that is resiliently deformable. Othermaterials may be used.

In one preferred embodiment, frame 112 is 18 cm (7 in) across at thehinges, and 16 cm (6.5 in) across in the orthogonal dimension. The framedefines an interior round area, having a diameter of about 15.24 cm (6in.), for an interior area of about 730 cm. In a preferred embodiment,frame 112 is made of stainless steel, as are the subassemblies.

While a number of exemplary aspects and embodiments have been discussedabove, those possessed of skill in the art will recognize certainmodifications, permutations, additions and sub-combinations thereof. Itis therefore intended that the following appended claims and claimshereafter introduced are interpreted to include all such modifications,permutations, additions and sub-combinations as are within their truespirit and scope.

The invention claimed is:
 1. A method of performing brain surgery on apatient having a skull and brain tissue, comprising: (a) creating anopening, having a rim, in said skull: (b) providing an assembly forfacilitating brain surgery, said assembly including: (i) a curved frame,defining an inward dimension and an outward dimension and defining aninterior area substantially larger than that defined by said opening insaid skull; (ii) a plurality of spatula arm subassemblies, eachincluding a spatula arm frame clamp, releasably attached to said frame,a spatula arm held and supported by said spatula arm frame clamp and aspatula extending from an inward end of said spatula arm; (iii) at leastone clamp arm subassembly, attached to said frame, including a clamp armframe clamp, releasably attached to said frame; a clamp arm having alongitudinal dimension, releasably held and supported by said clamp armframe clamp, and adjustable in position relative to said clamp arm frameclamp along said longitudinal dimension; and a skull clamp, supported bysaid clamp arm, and adapted to clamp onto said rim; and (iv) said skullclamp including a head and a tongue, extending downward from said head,and wherein said head defines a through hole, and wherein a bolt isengaged to said through hole and with said tongue, so that when saidbolt is tightened said tongue is lifted toward said head, therebyclamping any interposed element between said tongue and said head (c)clamping said assembly to said rim by means of said clamp armsubassemblies; (d) positioning said spatula arms so that the spatulasengage said brain tissue in a manner that facilitates surgery, by gentlyrestraining brain tissue to permit access to a target surgical location.2. The method of claim 1, wherein positioning said spatula arms includeschanging position of said spatula arm subassemblies on said frame. 3.The method of claim 1, wherein said spatula arm is rigid and has alongitudinal dimension and said spatula arm frame clamp permitsadjustment of said position of said spatula arm along its longitudinalaxis, relative to said spatula arm frame-clamp.
 4. The method of claim3, wherein said plurality of spatula arm subassemblies each furtherincludes pivot joints that permit vertical and horizontal location ofsaid spatula arm.
 5. The method of claim 1, wherein said spatula arm isflexible and holds its shape after being bent into a position, andwherein said each spatula arm is bent to position each said spatula tobeneficially restrain brain tissue, to facilitate surgery.
 6. The methodof claim 1, wherein said tongue is horizontally rotatable.